TY - JOUR
T1 - Neuroprotective mechanisms of minocycline against sphingomyelinase/ceramide toxicity
T2 - Roles of Bcl-2 and thioredoxin
AU - Tang, Ching Min
AU - Hwang, Chi Shin
AU - Chen, Shang Der
AU - Yang, Ding I.
PY - 2011/3/15
Y1 - 2011/3/15
N2 - In this study, we determined whether minocycline may protect rat cortical cultures against neurotoxicity induced by sphingomyelinase/ceramide and explored the underlying mechanisms. We found that minocycline exerted strong neuroprotective effects against toxicity induced by bacterial sphingomyelinase and synthetic C2 ceramide. Minocycline enhanced the production of nitric oxide (NO) with resultant increases in cellular cGMP content. Consistently, minocycline-dependent neuroprotection was abolished by the nitric oxide synthase inhibitor l-NG-nitroarginine methyl ester (L-NAME) and the soluble guanylate cyclase (sGC) inhibitor 1 H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one (ODQ). Western blotting revealed that minocycline restored the expression levels of cGMP-dependent protein kinase (PKG)-1, antioxidative thioredoxin-1, and antiapoptotic Bcl-2 that were down-regulated by bacterial sphingomyelinase. Accordingly, the PKG inhibitor KT5823, the thioredoxin reductase inhibitor 1-chloro-2,4-dinitrobenzene (DNCB), and a Bcl-2 inhibitor significantly abolished the minocycline neuroprotection. The minocycline-dependent restoration of Bcl-2 was abolished by L-NAME, ODQ, and KT5823, but not by DNCB, suggesting the involvement of NO/sGC/PKG but not thioredoxin. Furthermore, minocycline-dependent recovery of thioredoxin-1 was PKG-independent. Taken together, our results indicate that minocycline protects rat cortical neurons against bacterial sphingomyelinase/ceramide toxicity via an NO/cGMP/PKG pathway with induction of Bcl-2 and PKG-independent stimulation of thioredoxin-1.
AB - In this study, we determined whether minocycline may protect rat cortical cultures against neurotoxicity induced by sphingomyelinase/ceramide and explored the underlying mechanisms. We found that minocycline exerted strong neuroprotective effects against toxicity induced by bacterial sphingomyelinase and synthetic C2 ceramide. Minocycline enhanced the production of nitric oxide (NO) with resultant increases in cellular cGMP content. Consistently, minocycline-dependent neuroprotection was abolished by the nitric oxide synthase inhibitor l-NG-nitroarginine methyl ester (L-NAME) and the soluble guanylate cyclase (sGC) inhibitor 1 H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one (ODQ). Western blotting revealed that minocycline restored the expression levels of cGMP-dependent protein kinase (PKG)-1, antioxidative thioredoxin-1, and antiapoptotic Bcl-2 that were down-regulated by bacterial sphingomyelinase. Accordingly, the PKG inhibitor KT5823, the thioredoxin reductase inhibitor 1-chloro-2,4-dinitrobenzene (DNCB), and a Bcl-2 inhibitor significantly abolished the minocycline neuroprotection. The minocycline-dependent restoration of Bcl-2 was abolished by L-NAME, ODQ, and KT5823, but not by DNCB, suggesting the involvement of NO/sGC/PKG but not thioredoxin. Furthermore, minocycline-dependent recovery of thioredoxin-1 was PKG-independent. Taken together, our results indicate that minocycline protects rat cortical neurons against bacterial sphingomyelinase/ceramide toxicity via an NO/cGMP/PKG pathway with induction of Bcl-2 and PKG-independent stimulation of thioredoxin-1.
KW - Alzheimer disease
KW - Antioxidant
KW - Cerebral ischemia
KW - Cortical neurons
KW - Free radicals
KW - Nitric oxide
KW - Soluble guanylate cyclase
KW - cGMP-dependent protein kinase
UR - http://www.scopus.com/inward/record.url?scp=79951678468&partnerID=8YFLogxK
U2 - 10.1016/j.freeradbiomed.2010.12.024
DO - 10.1016/j.freeradbiomed.2010.12.024
M3 - 文章
C2 - 21184825
AN - SCOPUS:79951678468
SN - 0891-5849
VL - 50
SP - 710
EP - 721
JO - Free Radical Biology and Medicine
JF - Free Radical Biology and Medicine
IS - 6
ER -